Cooling apparatus, semiconductor module, and vehicle

ABSTRACT

The flow speed distribution of a refrigerant in a cooling apparatus is made uniform. A cooling apparatus provided includes: a top plate; a casing portion having a base plate facing the top plate, and a refrigerant delivery portion arranged between the top plate and the base plate, the casing portion provided with two opening portions to function as an inlet port through which a refrigerant is let into the refrigerant delivery portion and an outlet port through which the refrigerant is let out; a cooling fin portion arranged in the refrigerant delivery portion of the casing portion and between the two opening portions; and a loss adding portion arranged in the refrigerant delivery portion of the casing portion and between the cooling fin portion and at least one of the two opening portions, the loss adding portion generating pressure loss in the refrigerant passing therethrough.

The contents of the following Japanese patent application(s) areincorporated herein by reference:

NO. 2018-088899 filed in JP on May 2, 2018.

BACKGROUND 1. Technical Field

The present invention relates to a cooling apparatus, a semiconductormodule and a vehicle.

2. Related Art

In conventionally known configurations of semiconductor modulesincluding semiconductor elements such as power semiconductor chips,cooling apparatuses are provided (for example, see Patent Literatures 1to 2).

Patent Literature 1: Japanese Patent Application Publication No.2011-134979

Patent Literature 2: WO2015/177909

SUMMARY

The flow speed distribution of a refrigerant in a cooling apparatus ispreferably as uniform as possible.

In order to overcome the above-mentioned drawbacks, a first aspect ofthe present invention provides a cooling apparatus for a semiconductormodule including a semiconductor chip. The cooling apparatus may includea top plate. The cooling apparatus may include a casing portion that hasa base plate facing the top plate, and a refrigerant delivery portionarranged between the top plate and the base plate, the casing portionbeing provided with two opening portions to function as an inlet portthrough which a refrigerant is let into the refrigerant delivery portionand an outlet port through which the refrigerant is let out. The coolingapparatus may include a cooling fin portion that is arranged in therefrigerant delivery portion of the casing portion and between the twoopening portions. The cooling apparatus may include at least one lossadding portion that is arranged in the refrigerant delivery portion ofthe casing portion and between the cooling fin portion and at least oneof the two opening portions, the loss adding portion generating pressureloss in the refrigerant passing therethrough. Pressure loss that isgenerated when the refrigerant passes through the refrigerant deliveryportion of the casing portion from which the cooling fin portion isremoved, from one of the opening portions to the other opening portionmay be equal to or larger than 5 kPa.

The loss adding portion may be isolated from the cooling fin portion.

Pressure loss in the refrigerant passing through the cooling fin portionmay be smaller than pressure loss in the refrigerant passing through theloss adding portion.

When seen from above in a perpendicular direction to the top plate, anarea of a region provided with the cooling fin portion may be largerthan an area of a region provided with the loss adding portion.

The casing portion may have sidewalls extending from the base platetoward the top plate. When seen from above, the loss adding portion mayextend from a first sidewall to a second sidewall opposite to the firstsidewall.

The loss adding portion has a structure in which a plurality of openingsthrough which the refrigerant passes may be arranged discretely betweenthe first sidewall and the second sidewall.

The openings of the loss adding portion may be arranged at equalintervals.

Opening areas of the individual openings of the loss adding portion maybe equal.

The cooling fin portion may be provided with the refrigerant flowpassage through which the refrigerant passes. When seen from above, awidth of the openings of the loss adding portion may be smaller than awidth of the refrigerant flow passage of the cooling fin portion.

The at least one loss adding portion may include two loss addingportions, and the two loss adding portions are each provided between oneof the opening portions and the cooling fin portion.

The two opening portions may have different opening areas. Pressure lossat the loss adding portion corresponding to one of the two openingportions that has a larger opening area may be larger than pressure lossat the loss adding portion corresponding to one of the two openingportions that has a smaller opening area.

The loss adding portion may be at least partially provided detachably tothe refrigerant delivery portion.

A second aspect of the present invention provides a semiconductor moduleincluding: the cooling apparatus according to the first aspect; and asemiconductor device arranged above the cooling apparatus.

A third aspect of the present invention provides a vehicle including thesemiconductor module according to the second aspect.

The summary clause does not necessarily describe all necessary featuresof the embodiments of the present invention. The present invention mayalso be a sub-combination of the features described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view illustrating one example of asemiconductor module 100 according to one embodiment of the presentinvention.

FIG. 2 is a figure illustrating an arrangement example of a cooling finportion 94 and loss adding portions 30 on the x-y plane.

FIG. 3A is a figure illustrating a refrigerant delivery portion 92 fromwhich the cooling fin portion 94 is removed.

FIG. 3B is a figure illustrating the refrigerant delivery portion 92from which loss adding portions 30 are removed.

FIG. 4 is a figure illustrating another arrangement example of twoopening portions 42.

FIG. 5 is a figure illustrating another arrangement example of the twoopening portions 42.

FIG. 6 is a perspective view illustrating one example of the cooling finportion 94 and a loss adding portion 30.

FIG. 7 is a top view for explaining main points of the cooling finportion 94 and a loss adding portion 30.

FIG. 8 is a figure illustrating a structural example of a loss addingportion 30 on the y-z plane.

FIG. 9 is a top view illustrating another arrangement example of lossadding portions 30.

FIG. 10 is a figure illustrating main points of a vehicle 200 accordingto one embodiment of the present invention.

FIG. 11 is a main circuit diagram of the semiconductor module 100according to one embodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, (some) embodiment(s) of the present invention will bedescribed. The embodiment(s) do(es) not limit the invention according tothe claims, and all the combinations of the features described in theembodiment(s) are not necessarily essential to means provided by aspectsof the invention.

FIG. 1 is a schematic sectional view illustrating one example of asemiconductor module 100 according to one embodiment of the presentinvention. The semiconductor module 100 includes a semiconductor device70 and a cooling apparatus 10. The semiconductor device 70 in thepresent example is placed on the cooling apparatus 10. In the presentspecification, a surface of the cooling apparatus 10 on which thesemiconductor device 70 is placed is defined as the x-y plane, and aplane perpendicular to the x-y plane is defined as the z-axis. In thepresent specification, the direction from the cooling apparatus 10toward the semiconductor device 70 in the z-axis direction is referredto as the upward direction, and the opposite direction is referred to asthe downward direction, but the upward/downward direction is not limitedto the direction of gravity. In addition, in the present specification,among surfaces of each member, the surface on the upper side is referredto as the upper surface, the surface on the lower side is referred to asthe lower surface, and surfaces between the upper surface and the lowersurface are referred to as side surfaces.

The semiconductor device 70 includes one or more semiconductor chips 78such as power semiconductor chips. For example, a semiconductor chip 78is provided with an insulated-gate bipolar transistor (IGBT) formed in asemiconductor substrate such as a silicon substrate.

The semiconductor device 70 has a circuit substrate 76 and a housingportion 72. The circuit substrate 76 is, for example, an insulatingsubstrate provided with a circuit pattern. The semiconductor chips 78are fixed to the circuit substrate 76 via solder or the like. Thehousing portion 72 is formed of an insulating material such as a resin.The housing portion 72 has an internal space that houses thesemiconductor chips 78, the circuit substrate 76, wires, and the like.The internal space of the housing portion 72 may be filled with asealing portion 74 that seals in the semiconductor chips 78, the circuitsubstrate 76, wires and the like. The sealing portion 74 is aninsulating member such as a silicone gel or an epoxy resin, for example.

The cooling apparatus 10 has a top plate 20 and a casing portion 40. Thetop plate 20 may be a tabular metal plate having an upper surface 22 anda lower surface 24 that are parallel to the x-y plane. For example, thetop plate 20 is formed of an aluminum-containing metal. Thesemiconductor device 70 is placed on the upper surface 22 of the topplate 20. Heat generated by the semiconductor chip 78 is transferred tothe top plate 20. For example, thermally conductive members such as thecircuit substrate 76, a metal plate or solder are arranged between thetop plate 20 and the semiconductor chip 78.

The circuit substrate 76 may be fixed directly to the upper surface 22of the top plate 20 by solder or the like. In this case, the housingportion 72 is provided to surround a region of the upper surface 22 ofthe top plate 20 where the circuit substrate 76 and the like arearranged. In another example, the semiconductor device 70 may have ametal plate exposed to the lower surface of the housing portion 72, thecircuit substrate 76 may be fixed to the upper surface of the metalplate, and the metal plate may be fixed to the upper surface 22 of thetop plate 20.

The casing portion 40 is arranged to provide a refrigerant deliveryportion 92 between the lower surface 24 of the top plate 20 and a baseplate 64. The casing portion 40 may be formed integrally with the topplate 20, or may be formed as a separate member from the top plate 20.The refrigerant delivery portion 92 is a region where a refrigerant suchas water is delivered. The refrigerant delivery portion 92 may be atightly sealed space in contact with the lower surface 24 of the topplate 20. In addition, in a region on the x-y plane that surrounds therefrigerant delivery portion 92, the casing portion 40 is arranged toclosely adhere directly or indirectly to the lower surface 24 of the topplate 20. Thereby, the refrigerant delivery portion 92 is tightly sealedin. Note that “closely adhering indirectly” refers to the state wherethe lower surface 24 of the top plate 20 and the casing portion 40closely adhere to each other via a sealing material, an adhesive, oranother member that is provided between the lower surface 24 of the topplate 20 and the casing portion 40. “Closely adhering” refers to thestate where a refrigerant inside the refrigerant delivery portion 92does not leak through the closely adhering part.

A cooling fin portion 94 is arranged inside the refrigerant deliveryportion 92. The cooling fin portion 94 may be connected to the lowersurface 24 of the top plate 20. By causing a refrigerant to pass by thecooling fin portion 94, heat generated by the semiconductor chip 78 istransferred to a refrigerant. Thereby, the semiconductor device 70 canbe cooled. The casing portion 40 in the present example has a frameportion 62, the base plate 64 and a sidewall 63.

The frame portion 62 is arranged to surround the refrigerant deliveryportion 92 on the x-y plane. The frame portion 62 is arranged to closelyadhere directly or indirectly to the lower surface 24 of the top plate20. That is, the frame portion 62 and the lower surface 24 of the topplate 20 are provided to tightly seal in the refrigerant deliveryportion 92. A sealing material or another member may be provided betweenthe frame portion 62 and the lower surface 24 of the top plate 20.

In the present example, the top plate 20 and the casing portion 40 arebrazed. For example, the top plate 20 and the casing portion 40 areformed of metals with the same composition, and a brazing material isformed of a metal with a lower melting point than that of the top plate20 or the like.

The base plate 64 is arranged to provide the refrigerant deliveryportion 92 between itself and the lower surface 24 of the top plate 20.The sidewall 63 connects the frame portion 62 and the base plate 64 tothereby define the refrigerant delivery portion 92. The sidewall 63extends from the base plate 64 toward the top plate 20. The sidewall 63in the present example is provided with two or more opening portions 42through which a refrigerant is let into or let out of the refrigerantdelivery portion 92. A pipe 90 through which the refrigerant is conveyedis connected to the opening portions 42. In another example, the openingportions 42 may be provided to the base plate 64.

The top plate 20 and casing portion 40 are provided with through holes79 into which screws or the like for fastening them to each other areinserted. The through holes 79 may be used for fixing the semiconductormodule 100 to an external apparatus. The through holes 79 are providedin a region where the top plate 20 and the frame portion 62 are arrangedto closely adhere directly or indirectly and overlap in the z-axisdirection.

The cooling fin portion 94 is provided between the two opening portions42. One of the opening portions 42 sandwiching the cooling fin portion94 functions as an inlet port through which a refrigerant is let intothe refrigerant delivery portion 92, and the other opening portion 42functions as an outlet port through which a refrigerant is let out ofthe refrigerant delivery portion 92. Which opening portion 42 is causedto function as which of an inlet port or an outlet port can be selectedas appropriate by a user.

In addition, the refrigerant delivery portion 92 is provided with lossadding portions 30 that generate pressure loss in the refrigerantpassing through the refrigerant delivery portion 92. A loss addingportion 30 or loss adding portions 30 is/are arranged between thecooling fin portion 94 and at least one of the two opening portions 42.In the example shown in FIG. 1, each of the opening portions 42 isprovided with a loss adding portion 30.

The loss adding portions 30 generate pressure loss in the refrigerantpassing through the refrigerant delivery portion 92 to thereby make theflow speed distribution of the refrigerant in the refrigerant deliveryportion 92 uniform. A loss adding portion 30 may be provided over anentire cross-section of the refrigerant delivery portion 92 between thecooling fin portion 94 and an opening portion 42. The loss addingportion 30 may be a member in which blocking parts to block passage of arefrigerant and opening parts to allow passage of the refrigerant arearranged in a mesh pattern over the entire cross-section. By causing theloss adding portion 30 to generate large pressure loss, the pressure ofa refrigerant upstream of the loss adding portion 30 increases, and thepressure applied to surfaces of the loss adding portion 30 is equalized.Thereby, the flow speeds of the refrigerant passing through individualopening parts of the loss adding portion 30 can be equalized. Byproviding the loss adding portion 30 over the entire cross-section, theflow speed of the entire refrigerant flowing toward the cooling finportion 94 can be made uniform.

FIG. 2 is a figure illustrating an arrangement example of the coolingfin portion 94 and loss adding portions 30 on the x-y plane. In thepresent specification, the figure along the x-y plane is referred to asthe top view in some cases. In addition, in FIG. 2, regions on the x-yplane onto which circuit substrates 76 having semiconductor chips 78mounted thereon are projected are indicated by solid lines.

In the present example, the cooling fin portion 94 includes structuresthat are connected to the lower surface 24 of the top plate 20 andproject downward from the lower surface 24. In addition, the cooling finportion 94 includes the structures below the semiconductor chip 78 andstructures provided continuously from the structures. In addition,structures that have the same shapes as those of the structures belowthe semiconductor chip 78 and are arranged in the refrigerant deliveryportion 92 at predetermined intervals are included in the cooling finportion 94, even if those structures are isolated from the structuresbelow the semiconductor chip 78.

In the example shown in FIG. 2, structures 95 with wave shapes on thex-y plane are provided below semiconductor chips 78. The structures 95extend in the x-axis direction, and are arranged at constant intervalsin the y-axis direction. Each structure 95 is a tabular memberapproximately perpendicularly to the x-y plane. In the present example,all the structures 95 are treated as the cooling fin portion 94.

In another example, the cooling fin portion 94 may include columnarstructures that are approximately perpendicularly to the x-y plane andarranged in a predetermined pattern on the x-y plane. In anotherexample, the cooling fin portion 94 may be one formed by stacking, inthe z-axis direction, tabular structures that are provided approximatelyparallel to the x-y plane and are provided with openings to serve asrefrigerant flow passages. Note that structure of the cooling finportion 94 is not limited to them. Specific examples of structures inthe cooling fin portion 94 may be blades (tabular bodies), corrugatedbodies or pins. Blades may be straight-shaped, zigzag-shaped as shown inFIG. 2 or wave-shaped.

Loss adding portions 30 are provided over a predetermined entire y-zcross-section in the refrigerant delivery portion 92, for example. Theloss adding portions 30 extend from a first sidewall 63-1 of the casingportion 40 to a second sidewall 63-2 opposite to the first sidewall63-1. The loss adding portions 30 have shapes different from the coolingfin portion 94. In addition, the loss adding portions 30 may be providedbeing isolated from the cooling fin portion 94.

The cooling apparatus 10 is provided with loss adding portions 30 suchthat pressure loss that is generated when a refrigerant passes throughthe refrigerant delivery portion 92 of the casing portion 40 from whichthe cooling fin portion 94 is removed, from one opening portion 42 tothe other opening portion 42 becomes equal to or larger than 5 kPa.Pressure loss is the difference between the pressure of a refrigerantlet in from one opening portion 42 and the pressure of the refrigerantdischarged from the other opening portion 42. Pressure loss is measuredunder conditions of: an ethylene glycol 50 vol % solution as therefrigerant; the temperature of 65° C.; and the flow rate of 10 L/min.In an environment in which the semiconductor module 100 or an apparatuson which the semiconductor module 100 is implemented is operated, thecooling apparatus 10 may be used with a refrigerant at the temperatureof −40 to 120° C. being caused to flow at the flow rate of 3 to 20L/min, for example. Refrigerants that can be used include knownrefrigerants, for example, water or coolant (an ethylene glycol solutionwith the concentration of 30 to 70 vol %).

FIG. 3A is a figure illustrating the refrigerant delivery portion 92from which the cooling fin portion 94 is removed. In the state where thecooling fin portion 94 is removed, and loss adding portions 30 are leftunremoved, the loss adding portions 30 to attain pressure loss betweenthe two opening portions 42 of 5 kPa or higher are provided. Byproviding such loss adding portions 30, pressure loss increases, but theflow speed distribution of the refrigerant in the refrigerant deliveryportion 92 can be made uniform. The loss adding portions 30 may haveopening parts, through which a refrigerant is allowed to pass, havingthe same opening area. In addition, the loss adding portions 30 may haveopening parts that are distributed uniformly on the y-z plane. Even ifpressure loss increases, but if the power of a pump to let in therefrigerant is sufficiently high, the refrigerant can pass through therefrigerant delivery portion 92 at a certain speed or faster.

Pressure loss between the two opening portions 42 in the state where thecooling fin portion 94 is removed, and the loss adding portions 30 areleft unremoved may be equal to or lower than 10 kPa, may be equal to orlower than 8 kPa, or may be equal to or lower than 6 kPa. Thereby, it ispossible to prevent the energy loss from becoming excessively large.

As shown in FIG. 2, if the two opening portions 42 are provided atpositions to face each other in the x-axis direction, the flow speed ofa refrigerant passing through a refrigerant flow passage between the twoopening portions 42 becomes relatively fast. In contrast to this, byproviding the loss adding portions 30, the flow speed distribution of arefrigerant in the refrigerant delivery portion 92 could be madeapproximately uniform in the y-axis direction.

Note that pressure loss in the refrigerant passing through the coolingfin portion 94 may be smaller than pressure loss in the refrigerantpassing through the loss adding portions 30. If a plurality of lossadding portions 30 are provided, pressure loss in the refrigerantpassing through the loss adding portions 30 is measured in terms of thetotal sum of pressure loss at the plurality of loss adding portions 30.By increasing pressure loss at the loss adding portions 30, the flowspeed distribution of a refrigerant at the refrigerant delivery portion92 can be made uniform irrespective of the shape of the cooling finportion 94 or the like. Pressure loss at the loss adding portions 30 maybe twice as large as or three times as large as pressure loss at thecooling fin portion 94 or larger.

FIG. 3B is a figure illustrating the refrigerant delivery portion 92from which loss adding portions 30 are removed. The loss adding portions30 are removed, but the cooling fin portion 94 is left unremoved.Pressure loss between the two opening portions 42 in this state may beused as pressure loss at the cooling fin portion 94. Pressure lossbetween the two opening portions 42 in the state where the cooling finportion 94 is removed, and the loss adding portions 30 are leftunremoved like the state shown in FIG. 3A may be used as pressure lossat the loss adding portions 30. Alternatively, the difference betweenpressure loss measured in the state where the cooling fin portion 94 andloss adding portions 30 are left unremoved as shown in FIG. 2 andpressure loss measured in the state where the cooling fin portion 94 isremoved as shown in FIG. 3A may be used as pressure loss at the coolingfin portion 94. When seen from above, the width b in the x-axisdirection of the cooling fin portion 94 may be larger than each of thewidths a1, a2 in the x-axis direction of the refrigerant deliveryportion 92 in regions not provided with the cooling fin portion 94. Thatis, in the refrigerant delivery portion 92, the volume of each space inthe refrigerant delivery portion 92 before or after the cooling finportion 94 other than the space that corresponds to the region providedwith the cooling fin portion 94 may be smaller than the volume of thespace occupied by the cooling fin portion 94. The width b may be largerthan the sum of the widths a1 and a2.

FIG. 4 is a figure illustrating another arrangement example of the twoopening portions 42. The opening portions 42 in the present example areprovided to the sidewall 63-1 and the sidewall 63-2. In this case, itbecomes easier for a refrigerant let in from an opening portion 42 toflow along the y-axis direction. Because of this, it becomes easier forthe speed of a refrigerant passing through the cooling fin portion 94 tobecome faster at positions apart from the opening portions 42 in they-axis direction. In such an arrangement also, the flow speeddistribution of a refrigerant in the refrigerant delivery portion 92could be made uniform in the y-axis direction by providing loss addingportions 30.

FIG. 5 is a figure illustrating another arrangement example of the twoopening portions 42. The opening portions 42 in the present example arearranged at positions that are along sidewalls 63-3, 63-4 facing thecooling fin portion 94 in the x-axis direction and do not face eachother in the x-axis direction. In this case, it becomes easier for thespeed of a refrigerant passing through the cooling fin portion 94 tobecome faster at positions facing the opening portions 42. In such anarrangement also, the flow speed distribution in the refrigerantdelivery portion 92 could be made uniform by providing the loss addingportions 30. In this manner, the flow speed distribution of arefrigerant in the refrigerant delivery portion 92 could be made uniformin the y-axis direction by providing the loss adding portions 30,irrespective of the arrangement of the opening portions 42.

FIG. 6 is a perspective view illustrating one example of the cooling finportion 94 and a loss adding portion 30. The cooling fin portion 94 inthe present example has tabular structures 95 having wave shapes on thex-y plane that are arrayed at constant intervals in the y-axisdirection. Spaces between the structures 95 function as the refrigerantflow passage through which a refrigerant is allowed to pass.

On the x-y plane, the area of a region provided with the cooling finportion 94 is preferably larger than the area of a region provided withthe loss adding portion 30. Thereby, an increase of the apparatus sizethat may result because the loss adding portion 30 is provided can besuppressed. The area of the refrigerant flow passage between thestructures 95 on the x-y plane may be included in the area of thecooling fin portion 94. The area of the refrigerant flow passage betweenthe structures may be included similarly in the area of the loss addingportion 30. For example, the areas of the cooling fin portion 94 and theloss adding portion 30 used may be the area of the smallest rectanglecircumscribing the cooling fin portion 94 and the area of the smallestrectangle circumscribing the loss adding portion 30 on the x-y plane.

In the present example, the width of the cooling fin portion 94 and thewidth of the loss adding portion 30 in the y-axis direction are equal.In contrast to this, the width of the cooling fin portion 94 in thex-axis direction is larger than the width of the loss adding portion 30in the x-axis direction. In the x-axis direction, the width of the lossadding portion 30 may be 10% of the width of the cooling fin portion 94or smaller, or may be 5% of the width of the cooling fin portion 94 orsmaller.

FIG. 7 is a top view for explaining main points of the cooling finportion 94 and a loss adding portion 30. The cooling fin portion 94 inthe present example has a plurality of structures 95 that are arrayed inthe y-axis direction. Parts that are sandwiched by the structures 95function as refrigerant flow passages 96 that allow passage of arefrigerant from the side of one opening portion 42 to the side of theother opening portion 42. The loss adding portion 30 in the presentexample includes shields 31 and openings 32 that are arrangedalternately in the y-axis direction. The openings 32 are arrangeddiscretely between the sidewall 63-1 and the sidewall 63-2 as shown inFIG. 2. The openings 32 may be arranged discretely also in the z-axisdirection.

In the y-axis direction, the width W4 of the openings 32 of the lossadding portion 30 is smaller than the width W1 of the refrigerant flowpassages 96 of the cooling fin portion 94. The width W4 may be equal toor smaller than the width W1, or may be equal to or smaller than ¼ ofthe width W1. In addition, the width W4 of the openings 32 may besmaller than the width W3 of the shields 31. The width W4 may be equalto or smaller than the width W3, may be equal to or smaller than ¼ ofthe width W3, or may be equal to or smaller than 1/10 of the width W3.By making the width W4 of the openings 32 small, pressure loss at theloss adding portion 30 can be increased.

In addition, the pitch W3+W4 at which the openings 32 are provided maybe equal to or smaller than the pitch at which the refrigerant flowpassages 96 are provided (the sum W1+W2 of the width W1 of therefrigerant flow passages 96 and the width W2 of the structures 95). Thepitch W3+W4 may be smaller than the width W1 of the refrigerant flowpassages 96. By making the pitch W3+W4 small, at least one opening 32can be arranged for each refrigerant flow passage 96.

FIG. 8 is a figure illustrating a structural example of a loss addingportion 30 on the y-z plane. The loss adding portion 30 may have atabular shield 31 that is parallel to the y-z plane. The shield 31 isprovided over an entire y-z cross-section of the refrigerant deliveryportion 92. The shield 31 is provided with openings 32 that are arrangedtwo-dimensionally discretely. The openings 32 are preferably arranged atequal intervals on the y-z plane. In addition, the opening areas of theindividual openings 32 are preferably equal. Thereby, the flow speed ofa refrigerant on the y-z plane can be made uniform. Predeterminedmagnitudes of error may be tolerated for the openings to be regarded asbeing arranged at the equal intervals and having an equal area. Forexample, if errors between the intervals and the areas are within 5%,they may be regarded as equal intervals or the same areas.

The loss adding portion 30 may be one formed by punching the openings 32in a metal plate in a predetermined pattern. A loss adding portion 30 inanother example may be formed by wires such as metal wires being placedto cross each other, may be formed of plastic, or may be formed offibers.

FIG. 9 is a top view illustrating another arrangement example of lossadding portions 30. In the present example, a plurality of loss addingportions 30 are arrayed in the x-axis direction between at least oneopening portion 42 and the cooling fin portion 94. The structure of eachloss adding portion 30 is the same as the structure shown in FIG. 8, forexample. The individual loss adding portions 30 may be arranged apartfrom each other in the x-axis direction. The positions of the openings32 on the y-z plane may be different between the individual loss addingportions 30. With such a structure, the total sum of pressure loss atthe loss adding portions 30 can be increased. Note that the thickness ofone loss adding portion 30 in the x-axis direction may be equal to orsmaller than 1 mm.

In addition, the opening areas S1, S2 of the two opening portions 42 maybe different. The total sum of pressure loss at one or more loss addingportions 30 corresponding to an opening portion 42 with a larger openingarea may be larger than the total sum of pressure loss at one or moreloss adding portions 30 corresponding to an opening portion 42 with asmaller opening area. Thereby, variations in the flow speed can bereduced by increasing pressure loss on the side where variations in theflow speed easily occurs. In addition, a loss adding portion 30 may beprovided for an opening portion 42 with a larger opening area, and aloss adding portion 30 may not be provided for an opening portion 42with a smaller opening area.

In addition, at least some loss adding portions 30 may be attachable toand detachable from the refrigerant delivery portion 92. Thereby, thenumber of loss adding portions 30 provided between the opening portions42 and the cooling fin portion 94 can be adjusted, and pressure loss tobe generated can be adjusted.

FIG. 10 is a figure illustrating main points of a vehicle 200 accordingto one embodiment of the present invention. The vehicle 200 is a vehiclethat generates at least partial propulsive force using electric power.For example, the vehicle 200 is an electric car that generates entirepropulsive force using an electrically-driven device such as a motor, ora hybrid car that uses both an electrically-driven device such as amotor and an internal combustion engine driven using fuel such asgasoline.

The vehicle 200 includes a control apparatus 210 (an external apparatus)that controls an electrically-driven device such as a motor. The controlapparatus 210 is provided with the semiconductor module 100. Thesemiconductor module 100 may control electric power to be supplied tothe electrically-driven device. The vehicle 200 may be a large-sizedvehicle such as a bus, a heavy machine or a truck. In this case, itbecomes easy to use a large-sized pump as a pump to supply a refrigerantto the cooling apparatus 10, and the refrigerant can be supplied easilyto the cooling apparatus 10 with large pressure loss.

FIG. 11 is a main circuit diagram of the semiconductor module 100according to one embodiment of the present invention. The semiconductormodule 100 may be part of a vehicle-mounted unit that drives a motor ofa vehicle. The semiconductor module 100 may function as a three-phase ACinverter circuit having output terminals U, V and W.

Semiconductor chips 78-1, 78-2 and 78-3 may constitute a lower arm inthe semiconductor module 100, and a plurality of semiconductor chips78-4, 78-5 and 78-6 may constitute an upper arm in the semiconductormodule 100. A set of the semiconductor chips 78-1, 78-4 may constitute aleg. A set of the semiconductor chips 78-2, 78-5 and a set of thesemiconductor chips 78-3, 78-6 may similarly constitute legs. In thesemiconductor chip 78-1, the emitter electrode may be electricallyconnected to an input terminal N1, and the collector electrode may beelectrically connected to an output terminal U. In the semiconductorchip 78-4, the emitter electrode may be electrically connected to theoutput terminal U, and the collector electrode may be electricallyconnected to an input terminal P1. Similarly, in the semiconductor chips78-2, 78-3, the emitter electrodes may be electrically connected toinput terminals N2, N3, respectively, and the collector electrodes maybe electrically connected to output terminals V, W, respectively.Furthermore, in the semiconductor chips 78-5, 78-6, the emitterelectrodes may be electrically connected to the output terminals V, W,respectively, and the collector electrodes may be electrically connectedto input terminals P2, P3, respectively.

Each semiconductor chip 78-1 to 78-6 may be switched alternately by asignal input to a control electrode pad of the semiconductor chip 78. Inthis example, each semiconductor chip 78 may generate heat at the timeof switching. The input terminals P1, P2 and P3 may be connected to thecathode of an external power source, the input terminals N1, N2 and N3may be connected to the anode of the external power source, and theoutput terminals U, V, and W may be connected to the load. The inputterminals P1, P2 and P3 may be electrically connected to each other,and, in addition, the other input terminals N1, N2 and N3 may also beelectrically connected to each other.

In the semiconductor module 100, the plurality of semiconductor chips78-1 to 78-6 may each be an RC-IGBT (Reverse-Conducting IGBT)semiconductor chip. In the RC-IGBT semiconductor chips, IGBTs andfree-wheeling diodes (FWDs) may be formed integrally, and additionallythe IGBTs and FWDs may be connected in anti-parallel. The plurality ofsemiconductor chips 78-1 to 78-6 may each include a combination of atransistor such as a MOSFET or an IGBT and a diode. A chip substrate ofthe transistor and the diode may be a silicon substrate, a siliconcarbide substrate or a gallium nitride substrate.

While the embodiments of the present invention have been described, thetechnical scope of the invention is not limited to the above describedembodiments. It is apparent to persons skilled in the art that variousalterations and improvements can be added to the above-describedembodiments. It is also apparent from the scope of the claims that theembodiments added with such alterations or improvements can be includedin the technical scope of the invention.

The operations, procedures, steps, and stages of each process performedby an apparatus, system, program, and method shown in the claims,embodiments, or diagrams can be performed in any order as long as theorder is not indicated by “prior to,” “before,” or the like and as longas the output from a previous process is not used in a later process.Even if the process flow is described using phrases such as “first” or“next” in the claims, embodiments, or diagrams, it does not necessarilymean that the process must be performed in this order.

What is claimed is:
 1. A cooling apparatus for a semiconductor moduleincluding a semiconductor chip, the cooling apparatus comprising: a topplate; a casing portion that has a base plate facing the top plate, anda refrigerant delivery portion arranged between the top plate and thebase plate, the casing portion being provided with two opening portionsto function as an inlet port through which a refrigerant is let into therefrigerant delivery portion and an outlet port through which therefrigerant is let out; a cooling fin portion that is arranged in therefrigerant delivery portion of the casing portion and between the twoopening portions; and at least one loss adding portion that is arrangedin the refrigerant delivery portion of the casing portion and betweenthe cooling fin portion and at least one of the two opening portions,the loss adding portion generating pressure loss in the refrigerantpassing therethrough, wherein pressure loss that is generated when therefrigerant passes through the refrigerant delivery portion of thecasing portion from which the cooling fin portion is removed, from oneof the opening portions to the other opening portion is equal to orlarger than 5 kPa.
 2. The cooling apparatus according to claim 1,wherein the loss adding portion is isolated from the cooling finportion.
 3. The cooling apparatus according to claim 1, wherein pressureloss in the refrigerant passing through the cooling fin portion issmaller than pressure loss in the refrigerant passing through the lossadding portion.
 4. The cooling apparatus according to claim 3, wherein,when seen from above in a perpendicular direction to the top plate, anarea of a region provided with the cooling fin portion is larger than anarea of a region provided with the loss adding portion.
 5. The coolingapparatus according to claim 1, wherein the casing portion has sidewallsextending from the base plate toward the top plate, and when seen fromabove, the loss adding portion extends from a first sidewall to a secondsidewall opposite to the first sidewall.
 6. The cooling apparatusaccording to claim 5, wherein the loss adding portion has a structure inwhich a plurality of openings through which the refrigerant passes arearranged discretely between the first sidewall and the second sidewall.7. The cooling apparatus according to claim 6, wherein the openings ofthe loss adding portion are arranged at equal intervals.
 8. The coolingapparatus according to claim 7, wherein opening areas of the individualopenings of the loss adding portion are equal.
 9. The cooling apparatusaccording to claim 8, wherein the cooling fin portion is provided withthe refrigerant flow passage through which the refrigerant passes, andwhen seen from above, a width of the openings of the loss adding portionis smaller than a width of the refrigerant flow passage of the coolingfin portion.
 10. The cooling apparatus according to claim 1, wherein theat least one loss adding portion includes two loss adding portions, andthe two loss adding portions are each provided between one of theopening portions and the cooling fin portion.
 11. The cooling apparatusaccording to claim 10, wherein the two opening portions have differentopening areas, and pressure loss at the loss adding portioncorresponding to one of the two opening portions that has a largeropening area is larger than pressure loss at the loss adding portioncorresponding to one of the two opening portions that has a smalleropening area.
 12. The cooling apparatus according to claim 1, whereinthe loss adding portion is at least partially provided detachably to therefrigerant delivery portion.
 13. A semiconductor module comprising: thecooling apparatus according to claim 1; and a semiconductor devicearranged above the cooling apparatus.
 14. A vehicle comprising thesemiconductor module according to claim 13.